Add initial feed

The MCU board now lets the printer pull in the carrier until the new
paper in sensor is triggered for the first time and then starts the
print like before. The new "initial feed" provides an alignment of the
carrier which is exactly the same every time. Of course, the carrier now
needs two markings.

src/main.c

@@ -84,10 +84,21 @@ int main(void)
                 // blocked by carrier
                 if(HallSensorTimer < T_HALL_L && !(I_NPPINS & (1 << P_NPPINS)))
                 {
-                    // Block carrier
-                    O_CLUTCH |= (1 << P_CLUTCH);
+                    // Unblock carrier
+                    O_CLUTCH &= ~(1 << P_CLUTCH);
                     O_LED_GN |= (1 << P_LED_GN);
                     O_LED_RD &= ~(1 << P_LED_RD);
+
+                    State = AlignFeed;
+                }
+                break;
+            case AlignFeed:
+                // Check if carrier has moved to the first marked position
+                if(I_NPPINS & (1 << P_NPPINS))
+                {
+                    // Block carrier
+                    O_CLUTCH |= (1 << P_CLUTCH);
+
                     State = ClutchDelay;
                     MillisecondCounter = 0;
                 }
@@ -101,6 +112,15 @@ int main(void)
                     // Enable manual paper feed sensor
                     O_MNPFSO &= ~(1 << P_MNPFSO);
 
+                    State = WaitingForFeed;
+                }
+                break;
+            case WaitingForFeed:
+                // Check if the end of the alignment marking on the carrier is
+                // hit (this state is needed because the alignment marking would
+                // lead to skipping the WaitingForPaperIn state right away)
+                if(!(I_NPPINS & (1 << P_NPPINS)))
+                {
                     State = WaitingForPaperIn;
                 }
                 break;

src/main.h

@@ -7,14 +7,27 @@
 
 typedef enum
 {
-    PowerOnWait,
-    Idle,
-    ClutchDelay,
-    WaitingForPaperIn,
-    ExitOnDelay,
-    ManualPaperFeedOffDelay,
-    PaperInOffDelay,
-    ExitOffDelay
+    PowerOnWait,                        // Power-on test state with all outputs
+                                        // enabled
+
+    Idle,                               // Waiting for print job
+
+    AlignFeed,                          // Initial pulling in for proper align-
+                                        // ment of the carrier
+
+    ClutchDelay,                        // Delay before main carrier feed
+
+    WaitingForFeed,                     // Waits for the end of the carrier
+                                        // alignment mark
+
+    WaitingForPaperIn,                  // Waits for the paper in mark on the
+                                        // carrier
+
+    ExitOnDelay,                        // Wait for print to be completed
+
+    ManualPaperFeedOffDelay,            // Various delays
+    PaperInOffDelay,                    // for disabling the
+    ExitOffDelay                        // sensor signals again
 } State_t;
 
 int main(void);